The goal of this clinical trial is to learn if a 12-week individualized aerobic training program helps manage inactive or mildly active inflammatory bowel disease (IBD) including Crohn's disease (CD) and ulcerative colitis (UC) in adult patients aged 18-65 years. It will also assess participant compliance and the safety of the training program. The main questions it aims to answer are:

1. Does this aerobic training program improve the cardiopulmonary function of participants?
2. Does this aerobic training program help control disease activity?
3. Does this aerobic training program improve participants' quality of life?

Researchers will divide participants into two groups. One group will participate in the training program directly. The other group will first undergo a 12-week control intervention (i.e., standard treatment) before proceeding to the training program.

Participants will:

1. Take part in the individualized aerobic training program according to their baseline physical activity level for 12 weeks.
2. Visit the clinic once every 4 weeks for check-ups and tests.
3. Keep a diary of symptoms.

This study is a single-center, semi-crossover, randomized controlled trial. Patients will be consecutively screened from gastroenterology and inflammatory bowel disease clinics. After obtaining informed consent, they are randomly assigned in a 1:1 ratio, stratified by diagnosis (CD and UC). Group A immediately begins a 12-week individualized exercise training program, while Group B starts with a 12-week control intervention, consisting only of routine diagnosis and treatment, followed by the 12-week individualized exercise training. Comparisons are made for all patients before and after the exercise training and the control intervention.

Participants will be given different progressive individualized aerobic training schedules based on their baseline physical activity levels, with the exercise intensity increased every 4 weeks.

The implementation of the training program is based on telemedicine, utilizing a combination of methods including wearable devices, WeChat groups, and online form submissions to ensure quality control over the duration, intensity, and quality of the exercise training. Participants are required to wear fitness bands during the exercise training and use exercise software to record the exercise process, including duration, trajectory, maximal heart rate, and average heart rate. These data are promptly sent to the researchers upon completion of the exercise. Before the commencement of the exercise program, a dedicated researcher instructs the participants on how to use the bands to record the type of exercise, duration, and maximum heart rate, and then to timely fill in the exercise records on the online forms. Additionally, the researchers will discuss with the participants at the outset about the individualized exercise (including location, frequency, intensity, and type), the participants' motivation, expectations, and goals, as well as potential difficulties, aiming to enhance adherence to the training program.

Inclusion Criteria:

• Diagnosed with CD or UC for more than 3 months.
• Disease activity in remission or mildly active (CD: CDAI < 220; UC: pMS < 5).
• Baseline physical activity intensity is low, measured by the IPAQ Chinese version short form, and without a habit of "regular exercise".
• Agree to participate in the study and accept a 12-week individualized aerobic exercise training program.

Exclusion Criteria:

• Pregnant or breastfeeding, or planning to become pregnant within the next 3 months.
• Presence of physical movement disorders or other chronic diseases that limit physical activity.
• Having an ileostomy.
• History of anal or intestinal surgery within the past 3 months.

All IPD collected throughout the trial will be shared.

Start Date: Upon publication of this clinical trial. End Date: Five years following publication.

Who can access the data? Researchers who provide a methodologically sound proposal.

For what types of analysis? To achieve aims in the approved proposal. How can they access it? Proposals should be directed to drzhouying07@126.com. To gain access, data requestors will need to sign a data access agreement.